Continuous pelletizing, drying and bagging systems with improved throughput

ABSTRACT

The various embodiments of the present invention are directed to improved processes and systems for continuously bagging materials. In particular, the improved processes and systems can be used to bag tacky materials with improved throughput. The systems generally include at least one of a feeding section, mixing section, pelletizing section, transport piping, agglomerate catcher, defluidizing section, drying section, pellet diverter valve, and/or bagging assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. patent applicationSer. No. 13/202,926, filed 23 Aug. 2011, which claims the benefit ofInternational Patent Application Serial Number PCT/US2010/039513, filed22 Jun. 2010, which claims the benefit of U.S. Provisional PatentApplication Ser. No. 61/219,164, filed 22 Jun. 2009, all of which arehereby incorporated by reference in their entirety as if fully set forthbelow.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The various embodiments of the present invention generally relate toprocesses and systems for bagging pellets. More specifically, thevarious embodiments of the present invention relate to improvements inthe throughput capacity for the process of extruding, pelletizing,drying, and bagging of meltable and/or processable materials,specifically those that are tacky at least during processing, so as toprovide processes where the meltable and/or processable materials areextruded, pelletized, dried, and bagged continuously at increasedthroughput rates facilitated by those improvements.

2. Description of the Prior Art

The generally independent processes of, and equipment for use in,extrusion, pelletization, drying, and bagging of polymeric materials areknown and have been used in various applications. Over time, the demandfor processes and equipment capable of efficiently extruding,pelletizing, drying, and bagging materials and especially tackymaterials (e.g., asphalts, hot melt adhesives, and hot melt pressuresensitive adhesives) has increased. Commonly-assigned InternationalPatent Application No. PCT/US10/25255, which is incorporated herein byreference in its entirety as if fully set forth below, discloses acontinuous process for the efficient extrusion, pelletization, drying,and subsequent bagging of such materials.

Pelletization equipment and its use following extrusion processing havebeen implemented for many years by the assignee of the instantapplication, as demonstrated, for example, in commonly-assigned U.S.Pat. Nos. 4,123,207, 4,251,198, 4,500,271, 4,621,996, 4,728,276,4,888,990, 5,059,103, 5,403,176, 5,624,688, 6,332,765, 6,551,087,6,793,473, 6,824,371, 6,925,741, 7,033,152, 7,172,397, 7,267,540,7,318,719, 7,393,484, and 7,402,034; US Patent Application PublicationNos. 2009/0273112, and 2010/0040716; German Patent and Application Nos.DE 32 43 332, DE 37 02 841, DE 87 01 490, DE 196 42 389, DE 196 51 354,and DE 296 24 638; International Patent Application Publication Nos. WO2006/081140, WO 2006/087179, WO 2007/064580, WO 2007/089497, WO2007/142783, WO 2009/147514, and WO 2010/019667; and European PatentNos. EP 1 218 156, EP 1 556 199, EP 1 582 327, EP 1 841 574, EP 1 851023, EP 1 954 470, EP 1 970 180, EP 1 984 157, and EP 2 018 257. Thesepatents and patent applications are incorporated herein by reference intheir entireties as if fully set forth below.

Similarly, dryer equipment has been used by the assignee of the instantapplication, as demonstrated, for example, in commonly-assigned U.S.Pat. Nos. 3,458,045, 4,218,323, 4,447,325, 4,565,015, 4,896,435,5,265,347, 5,638,606, 6,138,375, 6,237,244, 6,739,457, 6,807,748,7,024,794, 7,171,762, and 7,524,179; US Patent Application PublicationNos. 2006/0130353, 2009/0110833, 2009/0126216, and 2010/0050458;International Patent Application Publication Nos. WO 2006/069022, WO2008/113560, WO 2008/147514, WO 2009/059020, and WO 2010/028074; GermanPatent and Application Nos. DE 19 53 741, DE 28 19 443, DE 43 30 078, DE93 20 744, and DE 197 08 988; and European Patent and Patent ApplicationNos. EP 1 033 545, EP 1 123 480, EP 1 602 888, EP 1 647 788, EP 1 650516, EP 1 830 963, EP 2 135 023, and EP 2 147 272. These patents andpatent applications are incorporated herein by reference in theirentireties as if fully set forth below.

BRIEF SUMMARY

Briefly, the various embodiments of the present invention includeseveral improvements over existing continuous as well as discontinuousprocesses and apparatuses, resulting in increased throughput capacity ofthose processes such that pellet blocking, pathway occlusion, undueadherence, sticture of pellets to that equipment, erosion, corrosion,abrasion and wear of the equipment are reduced and controlled.

These continuous processes and systems can be used on any type offormulation and are particularly advantageous to formulations ormaterials that are prone to be tacky and/or sticky at least during theprocessing steps. Additionally, these processes and systems areespecially beneficial for materials that can be tacky and/or stickyduring the processing steps and remain so or become so following thebagging or packaging step(s) of the processes. As used herein, the terms“tacky” or “sticky” refer to a material, component, or formulation thatduring and/or following processing is in the form of a pellet, granule,powder, or the like that can at least partially adhere to other items towhich it comes into contact. These materials, components, orformulations, hereinafter defined as “tacky materials,” can also beprone to cold flow as well as deformation under pressure (e.g., stackingand/or in bulk packaging). The tack or stickiness can also be due tomigration of components, liquid or solid, included in the formulation aswell as to migration and/or rearrangement of portions of the moleculescomprising those materials, components, or formulations, includingintermolecular and intramolecular phase separation as well as blush orbloom on the surface of the pellets, granules, powders and the like. Thetack and/or stickiness of the tacky materials can also arise as aconsequence of at least one of the processing steps, as a consequence ofthe formulation, as well as from packaging or storage, including suchconditions exposed to heat and/or pressure. The tacky materials are notlimited to those that are soft at ambient temperature.

A few illustrative examples of tacky materials include adhesives such aspolyamide adhesives, polyester adhesives, hot melt adhesives (HMA),pressure sensitive adhesives (PSA), hot melt pressure sensitiveadhesives (HMPSA), and the like. The tacky materials can also includesealants, asphalt and asphalt-containing materials, polymers,polymer-containing materials, as well as low molecular weight oligomersand polymers, high melt flow index materials including polymers,naturally occurring as well as synthetic materials including tackifiers,gum bases, waxes, rubber, rubber-like materials, and organic materials.These materials include those that retain their tack at ambienttemperature, possess or develop surface tack properties as a consequenceof processing and/or storage, as well as those that can undergodeformation, phase separation, and/or component migration contributingto tack or the development of tack as a consequence of processing and/orstorage wherein tack as defined herein includes stickiness.

Owing to the properties of these meltable and processable tackymaterials, it has been found that difficulties arise when extruding,pelletizing, drying, and bagging such materials. Such difficulties canarise at any point in the process from beginning to end. Feeding oftacky materials into an extrusion process is but one example of suchdifficulties. Pelletizing is particularly problematic with tackymaterials as is transportation through any piping between processingwherein even slight changes in temperature, change in direction of thepiping, constriction of the flow pathway, collision of the pelletsformed, flow rate of the transport fluid, and composition of thetransport fluid have significant impact due to the tacky nature of thematerials. Similarly dewatering and drying processes are subject toagglomeration, occlusion, sticture, and obstruction due to pelletinteractions and collisions, for example. Metal surfaces can beproblematic throughout the process and can require special treatmentsespecially wherein hang-up points are present. Any junctions wherepellet flow pathways are diverted can prove problematic includingbifurcated and/or gated pathways, for example. Individual packaging,bulk packaging, packaging materials, and storage conditions includingenvironmental and stacking considerations are important considerationsin the successful processing of tacky materials. And finally, equipmentconsiderations are important in overcoming the adhesion and stictureproblems as well as volume-related wear in processing such materials.

According to some embodiments, a system for continuously bagging a tackymaterial includes a feeding section configured to receive a tackymaterial; a mixing section configured to receive the tacky material fromthe feeding section and mix, melt, and/or blend the tacky material; apelletizing section configured to receive the tacky material from themixing section and pelletize the tacky material; a drying sectionconfigured to receive the tacky material from the pelletizing sectionand dry the pelletized tacky material. The system for continuouslybagging a tacky material further provides a pellet diverter valvecomprising: an inlet configured to receive an incoming flow of pelletsfrom the drying section; and at least a first and second outlet, eachconfigured to dispense an outgoing flow of pellets; and at least a firstand second bagging assembly in communication with at least the first andsecond outlets, respectively, of the pellet diverter valve, wherein theat least the first and second bagging assemblies alternatingly receive aspecific quantity of pellets from the pellet diverter valve to allowcontinuous bagging of the pellets.

According to other embodiments, a method for continuously bagging atacky material includes feeding a tacky material into a feeding section;mixing, melting, and/or blending the tacky material in a mixing section;pelletizing the mixed, melted, and/or blended tacky material in apelletizing section; drying pellets of the tacky material in a dryingsection; continuously diverting a specific quantity of the pelletsthrough one of a first and second outlet of a pellet diverter valve; andcollecting the specific quantity of pellets in a bag using a baggingassembly, wherein the bagging assembly is located at the first or secondoutlets of the pellet diverter valve.

According to other embodiments, a continuous bagging assembly deviceincludes a vertical forming tube having an input configured to receive aspecific quantity of pellets and an output configured to dispense thespecific quantity of pellets; a bagging material placed around and belowthe forming tube, wherein the bagging material is configured to collectthe specific quantity of pellets; and a horizontal sealing mechanismconfigured to seal the bagging material into individual bags forcontaining the specific quantity of pellets.

According to other embodiments, a system for continuously bagging tackymaterials includes a feeding section configured to receive a material,wherein the feeding section is optionally thermally controlled.

The system can also include a mixing section configured to receive thematerial from the feeding section and mix, melt, and/or blend thematerial. The mixing section can include a die having a removable insertwith a taper angle that is less than or equal to about 25 degrees. Insome cases, the taper angle of the removable insert is less than orequal to about 15 degrees. In other cases, the taper angle of theremovable insert is less than or equal to about 10 degrees.

There can be a gap between the removable insert and a body of the die,such that the gap is less than or equal to about 0.010 inches. In somesituations, the gap between the removable insert and the die body isless or equal to about 0.005 inches.

In some cases, a face of the removable insert can extend beyond asurface edge of the die body. For example, the face of the removableinsert can extend beyond the surface edge of the die body less than orequal to about 0.080 inches. In other situations, the face of theremovable insert can extend beyond the surface edge of the die body lessthan or equal to about 0.060 inches.

In some specific implementations of the system, the taper angle of theremovable insert is less or equal to about 10 degrees, a gap between theremovable insert and a body of the die is less than or equal to about0.005 inches, and the face of the removable insert extends beyond asurface edge of the die body is about 0.060 inches to about 0.080inches.

The die of the mixing section can have a die hole that has a land, whichis continuous.

The system can also include a pelletizing section configured to receivethe material from the mixing section and pelletize the material. Such apelletizing section can include a cutter hub that includes a blade angleof less than about 90 degrees, a blade cutting angle that is less thanor equal to about 20% less than the blade angle, and a blade traverseangle of about 0 degrees to about 55 degrees. The pelletizing sectioncan also include a transport fluid box that includes an inlet and anoutlet to reduce a velocity of transport fluid into and through thetransport fluid box. The inlet of the transport fluid box can direct aflow of transport fluid directly across a cutting face of a pelletizingdie, and the outlet can reduce any obstruction of pellets leaving thetransport fluid box by providing an open area.

The cutter hub of the pelletizing section is capable of beingstreamlined to have extended hexagonal cross-section. In some cases, theblade angle of the cutter hub can be about 20 degrees to about 60degrees. Similarly, the blade cutting angle of the cutter hub can beless than or equal to about 15% less than the blade angle. Also, theblade traverse angle can be about 20 degrees to about 55 degrees. Insome implementations, the cutter hub has a blade angle of about 30degrees to about 50 degrees, a blade cutting angle less than or equal toabout 15% less than the blade angle, and a blade traverse angle of about20 degrees to about 55 degrees.

The inlet and outlet of the transport fluid box can facilitate anenhanced flow rate and volume of the transport fluid across the face ofthe pelletizing die such that an increased volume of transport fluid ispresent relative to the number of pellets and such that the reducedconcentration of pellets is removed from the transport fluid box moreefficiently to reduce a likelihood of adhesion, sticture, andagglomeration of the pellets.

The system can also include a system of non-linear transport piping thatis downstream of the transport fluid box, such that the non-lineartransport piping includes long-radius angles.

The system can also include an agglomerate catcher that is downstream ofthe pelletizing section, wherein the agglomerate catcher includes anangled agglomerate removal grid, wherein an angle of inclination of theagglomerate removal grid is at least about 0 degrees. The non-lineartransport piping can be configured to allow transport of the materialfrom the pelletizing section to the agglomerate catcher. It is possiblefor the angle of inclination of the angled agglomerate grid to be atleast about 20 degrees. In some cases, the angle of inclination of theangled agglomerate grid is at least about 40 degrees. In other cases,the angle of inclination of the angled agglomerate grid is at leastabout 50 degrees.

The system can also include a defluidizing section that is downstream ofthe agglomerate catcher. The defluidizing section can include a pelletfeed chute that is partially blocked to prevent filtration of thetransport fluid from the material. Also, the defluidizing section doesnot include any obstructive baffles.

The system can further include a drying section, which is configured toreceive the material from the defluidizing section and dry thepelletized material. The drying section can include a dryer that itselfincludes a rotor with rotor blades in an upper portion of the rotor thatare at least about 10% narrower than rotor blades in a lower portion ofthe rotor, and at least two circumferential screens about the rotor suchthat at least a lowermost screen is a blank. In some situations, therotor blades in the upper portion of the rotor are at least 20% narrowerthan the rotor blades in the lower portion of the rotor. Alternatively,the rotor blades in the upper portion of the rotor can be at least 30%narrower than the rotor blades in the lower portion of the rotor.

The system can also include a pellet diverter valve that is downstreamof the drying section. The pellet diverter valve can be comprised of aninlet that is configured to receive an incoming flow of pellets from thedrying section, a housing, a housing offset, and at least a first andsecond outlet. The housing and housing offset can be configured suchthat a diverter flap moves inside the housing into the housing offset toprovide an open area through which the pellets traverse, wherein theopen area has a cross-sectional area that is no less than the pelletdiverter valve inlet. The first and second, and other, outlets are eachconfigured to dispense an outgoing flow of pellets. The diverter flap ofthe pellet diverter valve can be operated manually, electronically,hydraulically, automatically, and/or electromechanically.

The system can also have at least a first and second bagging assembly incommunication with at least the first and second outlets of the pelletdiverter valve, respectively. The first and second, and other, baggingassemblies can be configured to alternatingly receive a specificquantity of pellets from the pellet diverter valve to allow continuousbagging of the pellets.

In addition, within the system, a surface treatment can be applied to atleast a portion of a surface of a component of the feeding section,mixing section, pelletizing section, transport piping, agglomeratecatcher, defluidizing section, drying section, pellet diverter valve,and/or bagging assemblies. The surface treatment can be used to reduceabrasion, erosion, corrosion, wear, and undesirable adhesion andstricture. The surface treatment can include at least two layers suchthat the surface formed following treatment is three-dimensionallytextured. The at least two layers can be formed from at least one layerof a wear-resistant material that is uniformly overcoated with anon-stick polymer that only partially fills the three-dimensionalsurface texture of the at least one layer of wear-resistant material.For example, the at least one layer of wear-resistant component of thesurface treatment can be a ceramic, and/or the non-stick polymer of thesurface treatment can be a silicone, fluoropolymer, or a combinationthereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a flow chart of a continuous bagging process.

FIG. 2 illustrates a flow chart of the mixing, melting, and/or blendingportion of a continuous bagging process.

FIG. 3 is a schematic illustration of a diverter valve in various flowpositions, comprising: FIG. 3 a which is a schematic illustration of theexterior of the diverter valve; FIG. 3 b which illustrates the divertervalve in the operational position; and FIG. 3 c which illustrates thediverter valve in the external purge position.

FIG. 4 is a schematic illustration of the diverter valve with horizontalexternal purging, comprising: FIG. 4 a which is a schematic illustrationof a portion of the diverter valve rotated ninety degrees in relation toFIG. 3, for which FIG. 3 a is shown, to illustrate the horizontal purgechute; FIG. 4 b which is a top view of the diverter valve positionillustrating the operational position; FIG. 4 c which is a top view ofthe diverter valve position illustrating the horizontal external purgeposition directing flow into the horizontal purge chute; and FIG. 4 dwhich is a schematic illustration of a portion of the diverter valverotated ninety degrees in relation to FIG. 3 a to illustrate thehorizontal pipe for recycling.

FIG. 5 is a schematic illustration of the pelletizing section anddewatering and/or drying section between the mixing, melting, and/orblending section and the pellet diverting and bagging/packaging sectionsof the present invention.

FIG. 6 is a schematic illustration of a one-piece die plate with heatingelements in three configurations.

FIG. 7 a illustrates the three configurations of the heating elementextracted from the die plate.

FIG. 7 b illustrates the three configurations of the heating elementpositionally placed individually in side view.

FIG. 8 is a schematic illustration of a removable-center die.

FIG. 8 a is an expanded view illustration of a portion of theremovable-center die of FIG. 8.

FIG. 9 is an expanded view illustration of the components of a removablecenter-heated die.

FIG. 10 is a schematic illustration of a die body with transport fluidbox.

FIG. 11 is a schematic illustration of a die body and two-piecetransport fluid box.

FIG. 12 is an expanded view illustration of a comparative two-piecetransport fluid box.

FIG. 13 a is a schematic illustration of a complete assembly of acomparative two-piece transport fluid box.

FIG. 13 b is a cross-sectional illustration of an alternative transportfluid box inlet and outlet design.

FIG. 13 c is a schematic face-view illustration of the alternativetransport fluid box inlet and outlet design of FIG. 13 b.

FIG. 14 is a schematic illustration of a pelletizer with attachedtransport fluid box showing the die.

FIG. 15 is a schematic illustration of a die attached to a transportfluid box containing a flow guide.

FIG. 16 a is a schematic illustration of a comparative flow guide.

FIG. 16 b is a schematic illustration of a second configuration of acomparative flow guide.

FIG. 17 is a schematic illustration of a comparative flexible cutter hubwith exploded view of flexible hub component.

FIG. 18 a is a schematic view of a portion of a streamline cutter hub.

FIG. 18 b is a schematic view of the streamline cutter hub rotated inperspective relative to FIG. 18 a.

FIG. 18 c is a cross-sectional view of the streamline cutter hub in FIG.18 a.

FIG. 19 is an illustration of cutter blade designs and attachment anglesto cutter hubs showing the relative traverse angle of the blade cuttingedge to the die face, comprising: FIG. 19 a which is a schematicillustration of a comparative cutter hub with attached normal angleblade; FIG. 19 b which is a schematic illustration of a steep anglecutter hub with attached blade; FIG. 19 c which is a schematicillustration of a cutter hub with attached reduced thickness blade atnormal angle; and FIG. 19 d which is a partial top view schematicillustration of a cutter blade traversing across a die face and diehole.

FIG. 20 is a schematic illustration of a bypass loop.

FIG. 21 is an angled perspective illustration of an agglomerate catcherand grid.

FIG. 22 is an illustration of an alternative agglomerate catcherassembly configuration with an overflow attachment.

FIG. 23 is a schematic illustration of a dryer with attacheddefluidizing section.

FIG. 24 is a schematic illustration of a self-cleaning dryer.

FIG. 25 is a schematic illustration of a reservoir.

FIG. 26 is a schematic illustration of a dryer showing defluidizingscreen and centrifugal drying screen positioning.

FIG. 27 a is a schematic illustration of a prior art pellet divertervalve.

FIG. 27 b is a schematic illustration of the reverse view of the priorart pellet diverter valve in FIG. 27 a.

FIG. 28 is a schematic illustration of a pellet diverter valve assembly.

FIG. 29 is a schematic illustration of a cross-sectional view of apellet diverter valve assembly.

FIG. 30 is a schematic illustration of a cross-sectional view of afunnel and forming tube used for pellet bagging.

DETAILED DESCRIPTION

Referring now to the figures, wherein like reference numerals representlike parts throughout the several views, exemplary embodiments of thepresent invention will be described in detail. Although preferredembodiments of the invention are explained in detail, it is to beunderstood that other embodiments are possible. Accordingly, it is notintended that the invention is to be limited in its scope to the detailsof construction and arrangement of components set forth in the followingdescription or illustrated in the drawings. The invention is capable ofother embodiments and of being practiced or carried out in various ways.Also, in describing the preferred embodiments, specific terminology willbe resorted to for the sake of clarity. Throughout this description,various components may be identified having specific values orparameters, however these items are provided as exemplary embodiments.Indeed, the exemplary embodiments do not limit the various aspects andconcepts of the present invention as many comparable parameters, sizes,ranges, and/or values may be implemented.

The continuous bagging system, shown as a flow chart in FIG. 1, includesat least one feeding or filling section 2 that provides material(s) thatcan include tacky material(s) into a mixing, melting and/or blendingsection 4. This mixing section 4 is coupled to a pelletizing section 6that is subsequently connected via a transport system to adewatering/drying section 8. Upon exiting the dewatering/drying section8, pellets pass into and through a pellet diverting section 10 and aresubsequently and ultimately fed into a bagging/packaging section 12.

Tacky materials as disclosed herein without intending to be limited caninclude adhesives such as polyamide adhesives, polyester adhesives, hotmelt adhesives (HMA), pressure sensitive adhesives (PSA), hot meltpressure sensitive adhesives (HMPSA), and the like. The tacky materialscan also include sealants, asphalt and asphalt-containing materials andformulations, polymers and polymer-containing materials as well asformulations, as well as low molecular weight oligomers and polymers,high melt flow index materials including polymers, naturally occurringas well as synthetic materials including tackifiers, waxes andwax-containing formulations, gum bases and gum base formulations,rubber, rubber-like materials, and organic materials. Examples of tackyrubber and rubber-like materials can include ethylene-propylenecopolymers and terpolymers, EPDM rubber, natural rubber,isobutylene-isoprene copolymers, butyl rubber, polyisoprene,poyisobutylene, polybutadiene, halogenated butyl rubber,polychloroprene, polysulfides, poly epoxides and copolymers,polypropylene oxide and copolymers, polepichlorohydrin, chlorinatedpolyethylene, silicone rubbers, styrene-butadiene copolymers,butadiene-acrylonitrile copolymers, urethane elastomers, halogenatedethylene-propylene copolymers, polyethacrylate including blends of theabove as well as plasticized compositions and combinations of the above.These materials include those that retain their tack at ambienttemperature, possess or develop surface tack properties as a consequenceof processing and/or storage, as well as those that can undergodeformation, phase separation, and/or component migration contributingto tack or the development of tack as a consequence of processing and/orstorage wherein tack as defined herein includes stickiness. The tackymaterials can also be used as components of other formulations or can bethe final product.

An exemplary continuous bagging process for tacky materials generallyincludes feeding the material(s) that can include tacky material(s) fromthe feeding or filling section 2 to the mixing, melting, and/or blendingsection 4 to which can be added additional material(s) that can includetacky material(s) as needed. The material or combined materials are thenmixed, melted, and/or blended in at least one vessel that can includeone or more extruders alone and in many combinations. The now moltenmaterial, preferably uniformly admixed, is extruded through a pelletizerin pelletizing section 6. Following transport, the pellets are sent intoand through a dewatering and/or drying device in the dewatering/dryingsection 8 from which the now dewatered and/or dried pellets pass intoand through the pellet diverting section 10. The pellets can be divertedor directed out of the processing, or directed into and through thebagging section 12 for subsequent bagging and/or packaging. The divertedpellets can be discarded, reprocessed and/or used directly, foradditional processing and/or for post-processing as needed.

Continuing with FIG. 1, the feeding or filling section 2 can include atleast one of manual, gravity, and automated feeders and feedingprocesses. The material being fed can be solid or liquid and can bedelivered by weighing, mass-balance transfer, and/or volumetricprocesses as are known to those skilled in the art. The feeders can becooled to temperatures below the tack point of the material to provideproper conveyance for tacky materials as well as below the freezingpoint for low melting materials for proper solid conveyance. Solidmaterials can be fed as powders, granules, pellets, particles, and thelike. These materials, particularly tacky solid materials, can be coatedprior to the feeding process to reduce or eliminate the tack forenhanced feeding.

Alternatively the materials to be fed, including tacky materials, can bemelted prior to introduction into the feeders for delivery as a liquid.Such molten materials can be provided by transfer from upstreamprocesses as, for example, from heated storage containers and railroadcars. Drum heaters, both internal and external, can be used to meltmaterials in drums or similar storage containers as well. These moltenmaterials as well as liquid materials can then be transported to thefeeders by feed screw, pumps, or other comparable devices as are knownto those skilled in the art. Similarly, liquid materials can be fed bysiphoning processes utilizing partial vacuum. This is particularlyimportant for reactive and/or moisture-sensitive materials, for example.

These materials are introduced into the mixing, melting, and/or blendingsection 4 of FIG. 1. These processes can be accomplished by use of oneor more thermally regulated vessels, extruders, and/or static mixers.

Vessels can include mixers containing motor-operated rotors to which arefixedly attached mixing blades that can be propeller or boat-style,ploughshare style, delta style or sigma style including single, double,and multiple configurations. Helical or helical dispersion blades canalso be used. Alternatively, ribbon blenders, Banbury-type blenders,horizontal mixers, vertical mixers, planetary mixers, and otherequivalent devices can be used as known to those skilled in the art.

Various levels of mixing and shear are achieved by the differing stylesof blades and mixer designs. For example, higher shear blades arepreferred for components such as rubbers or cross linkable materials andthermally sensitive materials. Energy is introduced into the materialsmechanically by the shear as well as thermally by the physical heatingprocess. Propeller style blades are preferred for physical mixing whereless or no shear is required to achieve uniformity of blending. Thermalcontrol of the vessel may be achieved electrically, by steam, or bycirculation of heat tempering fluids such as oil or water, for example.The vessel chamber can be atmospheric, under vacuum or reduced pressure,as well as purged with air or an inert gas (e.g., nitrogen, argon, orthe like).

Mixing, melting and/or blending can also be achieved using at least onesingle, twin, and/or multiple screw extruder such as a ring extruder.The sections of the screw must feed, mix, and convey the material(s)simultaneously providing sufficient thermal and/or mechanical energy tomelt, mix, shear, and/or uniformly disperse the material or materials.The extruder, particularly the twin and multiple screw extruders, can bepurged with air or other inert gas such as nitrogen or alternatively canbe evacuated at one or more ports to remove gases, volatiles, or otherunwanted materials. Multiple feeding and injection ports can be addedalong the barrel of the screw as required to allow addition of solid orliquid ingredients to the material in process as needed. Configurationof the screw must be satisfactory to achieve an appropriate level offeeding, mixing, melting, blending, and throughput as necessitated bythe specific process. The extruder can also be used to cool the materialbeing processed in at least one zone of the extruder to improve orincrease viscosity, confer thermal stability, and/or reduce volatilityfor example.

Liquid or molten materials including formulations from upstream sourcesincluding storage areas, vessels, and/or extruders can be pumped into astatic mixer for additional mixing and thermal processing. Thesefluid-like materials are pressurized using a booster pump that can be acentrifugal or positive displacement reciprocating or rotary pump. Therotary pump can be a peristaltic, vane, screw, lobe, progressive cavity,or gear pump. To generate moderate pressures ranging from approximately150 pounds per square inch (psi) to approximately 500 psi, an openclearance gear pump is preferable, whereas a high precision gear pumpwould be more appropriate to generate higher pressures in excess ofapproximately 500 psi.

The pressurized melt can optionally be processed through a coarse filtersuch as a candle filter, basket filter, or screen changer to removelarger particles, agglomerates, or remaining granular material.Preferably a basket filter of 20 mesh or coarser requiring only moderatepressure is used when coarse filtration is necessitated by the materialbeing processed. When additional filtration or finer particulatefiltration is essential to the process, a basket filter and preferably ascreen changer can be used. Preferably, a screen changer of 200 mesh orcoarser is used, and more preferably a multilayer screen changer of twoor more screens is used. Even more preferably, filtration through amultilayer screen changer of two or more screens of differing mesh canbe used, and most preferably the multilayer screen changer comprises aseries of filters (e.g., 20 mesh, 40 mesh, and 80 mesh filters).Alternatively, the multilayer screen changer can comprise a sandwich ofscreens such that the finer mesh screen is between two coarser screens,thus providing coarse filtration as well as providing additionalstructural support to the screen assembly. Exemplary of this is amultilayer screen sandwich comprising a series of filters of 20 mesh,200 mesh, and 20 mesh. To achieve the most preferable filtration, a gearpump capable of generating pressure ranging from approximately 500 psito approximately 2000 psi can be used. The screen changer as describedhereinabove can be manual, plate, slide plate, or single or dual bolt indesign, and can be continuous or discontinuous in operation. Thepressure generated must be sufficient to force the melt through thecomplete filtration process as well as into and through the thermallyregulated static mixer.

The mixing, melting, and/or blending section 4 is summarized in the flowchart in FIG. 2. Material can be transferred by the feeding section 2 tothe mixing, melting, and/or blending section 4 as indicated by arrow 50to vessel 40 or as by arrow 52 to extruder 42 or alternatively as shownby arrow 54 to static mixer 48. Additionally and optionally, materialcan be passed from vessel 40 to extruder 42, or the reverse as indicatedby dotted bidirectional arrow 56. Similarly, and optionally, materialcan be passed from vessel 40 to static mixer 48 or the reverse asindicated by bidirectional arrow 60 with still another alternative beingthe passage of material from extruder 42 to static mixer 48 and thereverse indicated by bidirectional arrow 58. Monodirectional arrow(s) 62indicates that material can be processed optionally by at least one pump44 through at least one filter 46 to provide sufficient pressure tofacilitate the flow of material to and through static mixer 48regardless of the source (i.e., whether the source is the feedingsection 2, vessel 40, and/or extruder 42). Therefore, a multiplicity ofpathways and equipment are illustrated in FIG. 2 as detailed above. Itshould be understood that the molten material can also be transported(e.g., by pumping) to a remote storage area or facility and maintaineduntil such time as it is ready to be further processed.

Dotted line 70 indicates that material from the vessel 40 can be passedto the pelletizing section 6 detailed below. Similarly, material fromextruder 42 can be passed as shown by dotted line 72 to pelletizingsection 6, and material from static mixer 48 can be passed according todotted line 74 to pelletizing section 6. An optional pump 80 as well asan optional filter 82 can be used to facilitate the passage of materialsfrom the mixing, melting, and/or blending section 4 to pelletizingsection 6 into and through at least one diverter valve 84. Anotheroptional diverter valve 84 can be placed between filter 46 and staticmixer 48 as illustrated in FIG. 2. Pump 44 and pump 80 can be the sameor different, for example, according to the above description whereinpump 80 preferably is capable of generating pressures greater thanapproximately 500 psi (and more preferably approximately 500 psi toapproximately 2000 psi and greater as necessitated by the material beingprocessed). Filter 46 and filter 82 can be the same or different,wherein filter 82 preferably is a multilayer screen changer of two ormore screens of differing mesh size, and is most preferably a multilayerscreen changer comprising a series of filters. The mixing, melting,and/or blending section 4 is also described in commonly-assignedInternational Patent Application Publication No. WO 2007/064580, whichis incorporated herein by reference as if fully set forth below.

The optional diverter valve 84 in FIG. 2, and illustrated in detail inFIG. 3, is connected directly or by a suitable transition to either theoutlet of the final component of the mixing, melting, and/or blendingsection 4 or to the outlet of optional pump 80 or optional filter 82.The outlet of the appropriate component or transition is attached toinlet 88 of diverter valve 84 illustrated in FIG. 3 a. Both inlet 88 andoutlet 90 are coupled to housing 86. Two or more modes of flow areavailable through diverter valve 84 as illustrated in FIGS. 3 b and 3 c.

In the operational flow mode shown in FIG. 3 b, flow proceeds throughinlet 88 into inlet tube 92, which is in open communication with flowpathway 94 through the movable diverter bolt 96. Flow progresses throughflow pathway 94, which is in open communication with outlet tube 98 andoutlet 90. One or more modal pathways may be so constructed inpositionally differing arrangements so as to allow one or more flowpathways to be available.

Similarly, in the “divert flow” mode illustrated in FIG. 3 c, flowproceeds through inlet 88 into inlet tube 92, which is in opencommunication with flow diversion pathway 100 through the movablediverter bolt 96. Flow progresses through flow diversion pathway 100,which is in open communication with diversion outlet 102. Molten,liquid, or extruded material can be diverted or removed from the processvia this pathway.

FIG. 4 illustrates the diverter valve 84 as designed to allowside-discharge of the diverted flow. FIG. 4 a illustrates a 90° rotationof the diverter valve 84 from FIG. 3 a to show the attachment ofdiverter chute 104 to the housing 86. Alternatively, the diverted flowcan pass through diversion pipe 106 similarly attached to housing 86 asillustrated in FIG. 4 d. As in FIG. 3, two or more modes of flow areavailable through the diverter valve 84 as illustrated in FIGS. 4 b and4 c. In the operation flow mode shown in FIG. 4 b, flow proceeds throughinlet 88 into inlet tube 92, which is in open communication with flowpathway 108 through the movable diverter bolt 110. Flow progressesthrough flow pathway 108, which is in open communication with outlettube 98 and outlet 90. One or more modal pathways can be so constructedin positionally differing arrangement so as to allow one or more thanone flow pathway to be available.

Similarly, in the divert flow mode illustrated in FIG. 4 c, flowproceeds through inlet 88 into inlet tube 92, which is in opencommunication with flow diversion pathway 112 through the movablediverter bolt 110. Flow progresses through flow diversion pathway 112,which is in open communication with diversion outlet tube 114. Molten,liquid, or extruded material can be diverted, as for recycling forexample, or removed from the process via this pathway. The diverted flowpasses through diversion outlet tube 114 to and through outlet 116 towhich can be connected diverter chute 104 or diversion pipe 106 asillustrated in FIGS. 4 a and 4 d, respectively.

Inlet tube 92 can be decreasingly tapered as shown in FIGS. 3 b, 3 c, 4b, and 4 c. Alternatively, inlet tube 92 is cylindrical in diameter,which is dimensionally consistent with either the outlet from themixing, melting, and/or blending section 4 (FIG. 2) or an appropriateoptional transition. The continuous diameter is preferable to avoid anydimensional reduction of the flow pathway wherein adhesion or stictureof tacky materials can be processed. Without intending to be bound byany theory, reduction of the flow pathway can result in increasedpressure and/or shear that can manifest itself as undesirable increasedtemperature with subsequent reduction of viscosity. Diversion outlettube 114 can be cylindrical, increasingly tapered, and the like, butcannot be decreasingly tapered for the reasons stated hereinabove.Outlet tube 98 is increasingly tapered to outlet 90 so as todimensionally accommodate components of the pelletization section 6 asdescribed below.

The components in sections 2 and 4 of FIGS. 1 and 2 including vessels,extruders, gear pumps, screen changes, diverter valves (FIGS. 3 and 4),and static mixers can be surface treated and/or coated. Nitriding,carbonitriding, electrolytic plating, electroless plating, thermalhardening, flame spray techniques, and sintering techniques areexemplary surface treatment and coating techniques. By way ofillustration, International Patent Application Publication No. WO2009/059020, which is incorporated herein by reference in its entiretyas if fully set forth below, describes such techniques.

Turning now to FIG. 5, and following from FIGS. 1 and 2, the mixing,melting, and/or blending section 4 is connected to the optional divertervalve 84 at inlet 88. The diverter valve in turn is coupled throughoutlet 90 to the inlet 310 of die 300 with details illustrated in FIGS.6, 7 a, 7 b, 8, and 9.

The die 300 in FIG. 6 is a single-body style die, including a nose cone322 attached to die body 320 into which are fitted heating elements 330and through which are bored multiple die holes 340 that vary in numberand orientation pattern. The die holes 340 preferably have a diameter ofless than or equal to about 3.5 millimeters (mm). The die holes 340 canbe have many designs, including increasing taper, decreasing taper,cylindrical, and the like, and combinations thereof. Segments of the dieholes 340 can vary in length as necessitated by the process andmaterials. Preferably, the die holes 340 are placed singularly orcollectively in groups or pods in one or more concentric rings asdetermined by the diameter of the outlet 90 of the diverter valve 84,which is coupled thereto.

Heating elements 330 can be a cartridge or coil type element, and can beof sufficient length inside the die body 320 to remain outside thecircumference of the die holes (e.g., as illustrated in FIG. 6 anddetailed in FIGS. 7 a and 7 b as configuration 1). The heating elements330 can extend into and near the center of the die body without passingthe center in length (e.g., configuration 2 in FIGS. 7 a and 7 b), orcan extend past the center in length but not of sufficient length tocontact the ring of die holes diametrically opposed, (e.g.,configuration 3 in FIGS. 7 a and 7 b). Positioning of the die holes willvary as would be readily recognized by those skilled in the art toaccommodate the appropriate configuration of the heating elements 330,and one or more lengths or designs of the heating elements 330 can beimplemented.

A preferred design of die 300 is illustrated in FIG. 8 in that the diebody is of a removable center or insert configuration. The heatingelements 330 are of a cartridge or coil configuration and are insertedinto the outer die body component 352 whereby they are constrained inlength to suitably fit within the confines of the outer die bodycomponent 352. The die holes 340 are contained within removable insert350 and are variable in design, dimension, and placement as detailedabove.

For tacky materials, for example, the lands of the die holes 340preferably are continuous, or are significantly continuous in diametersuch that following the introduction of the molten material into the diehole it is not subjected to additional compression and/or shear as wouldbe introduced by any decrease in diameter of the land of that die holeand thus does not experience a reduction in viscosity due to any suchdifferences. The positioning of the die holes 340, particularly fortacky materials, is also of significant importance in that spacing needsto be such that on extrusion and pelletization, as describedhereinbelow, the pellets being formed do not readily come in contactwith each other, thus avoiding unwanted adhesion, sticture, and/oragglomeration of those pellets. Such positioning must further take intoconsideration any die swell that the material experiences as aconsequence of its progress through, and egress from, the die holes. Theremovable insert 350 can be coupled to outer die body component 352using ordinary mechanisms as would be understood by those skilled in theart.

In a more preferred configuration for die 300 as illustrated in FIG. 8and expanded in detail in FIG. 8 a, the taper angle 370 that the edge ofthe removable insert 350 makes relative to a perpendicular line drawnfrom one of the parallel faces of the removable insert 350 is less thanapproximately 25°. As the control of the thermal uniformity of the diebecomes more significant, as in low viscosity tacky materials, forexample, where subtle to minor temperature changes can make largedifferences in that viscosity, the taper angle 380 is preferablyapproximately 15° or less, and more preferably less than approximately10°. As the taper angle is decreased, it was found to be surprising thatwithdrawal of the removable insert 350 becomes increasingly difficultsuch that a gap 382 between the removable insert 350 and the outer diebody component 352 becomes necessary. Preferably, the gap 382 is lessthan approximately 0.010 inches (approximately 0.25 mm), and morepreferably the gap 382 is less than approximately 0.005 inches(approximately 0.13 mm). It was also surprising that a slight extension384 of the removable insert 350 past the surface edge of the outer diebody component 352 enhanced the quality of the material beingpelletized. The extension 384 is preferably less than approximately0.080 inches (approximately 2.0 mm), and more preferably is in a rangefrom approximately 0.060 inches to approximately 0.080 inches(approximately 1.5 mm to approximately 2.0 mm). In a still morepreferred configuration, as by way of example for highly tacky and lowviscosity materials, the removable insert 350 has a taper angle 380 ofless than approximately 10°, and a gap 382 of less than approximately0.005 inches (approximately 0.13 mm), and an extension 384 in a rangefrom approximately 0.060 inches to approximately 0.080 inches(approximately 1.5 mm to approximately 2.0 mm).

Similarly, where viscosity or tack is less significant or where thecontrol of the thermal uniformity in this particular processing step isnot important, the taper angle 380 can be increased to greater thanapproximately 25° and preferably can be in a range from approximately25° to approximately 45° and greater. As this thermal control is now notas rigorous, the gap 382 necessary for the lower taper angle is nolonger significant and the extension 384 is no longer of requisiteimportance.

FIG. 9 shows an alternative design of die 300 in that the die body is ofa removable center or insert configuration with multiple heating zonesfor enhanced heating efficiency and more facile thermal transfer to themolten or liquid materials as they pass through the die holes 340. Theouter die body component, not shown, is comparable to that described forFIG. 8. The heated removable insert 360 of the alternative design has anopen center to which is fitted a heating element 365, preferably acoiled heating element, that can be thermally controlled in common withother heating elements in the outer die body component or morepreferably, is autonomously regulated thermally thus allowing multizoneheating capacity within the die 300.

The die 300 in all configurations (FIGS. 6, 8, and 9) can contain anappropriate hardface 370 for a cutting surface, as illustrated in FIG.9, that is preferably an abrasion resistant, wear resistant, and, whererequired, corrosion resistant material and through which pass the dieholes 340 for extrusion of the molten or liquid extrudate. For example,tungsten carbide, titanium carbide, and the like, and ceramics ormixtures thereof, either alone or in combination, are but a few examplematerials for hardface applications. Similarly, the die 300 in allconfigurations (FIGS. 6, 8, and 9) can be insulated die designs, asdescribed in International Patent Application Publication No. WO2010/019667, which incorporated by reference in its entirety as if fullyset forth herein.

In addition, the die 300 can undergo surface treatments, surfacefinishing, polishing, or hard surfacing (e.g., nickel phosphide, chromeplating, nitriding, or a comparable physical or chemical treatment) toprovide additional protection to the die body.

A bolting mechanism for the nose cone 322 is illustrated in FIG. 9. Acover plate 372 is positionally attached by bolt 374 to the face of thedie body 320, removable insert 350, or heated removable insert 360, asshown in FIGS. 6, 8, and 9, respectively. The cover plate 372 can beless than or at least equal to the height dimension of the hardface 370.Alternatively, a gasket material or other materials for sealing of thecover plate 372 can be used as desired.

Diverter valve outlet 90 is comprised of an inner bore that is tapereddiametrically and conically in increasing diameter to create a chambercontinuously and proportionately larger than nose cone 322 that insertstherein. The volume of the resulting chamber allows unobstructed flow ofthe polymeric material or other molten or liquid material to flow fromthe diverter valve 84 into the die hole 340. Alternatively, an adapteror transition can be attached to diverter valve outlet 90, which isaccordingly tapered to accommodate the nose cone 322.

The diverter valve outlet 90 and alternative adapter, nose cone 322, anddie body 320 in FIGS. 6, 10, and 11, the removable insert 350 of FIG. 8,and the heated removable insert 360 of FIG. 9, can be made of carbonsteel, thermally hardened carbon steel, stainless steel (includingmartensitic and austenitic grades), thermally hardened andprecipitation-hardened stainless steel, or nickel to improve resistanceto abrasion, erosion, corrosion, and wear. Nitriding, carbonitriding,electrolytic plating and electroless plating techniques can be used toenhance these resistance properties.

To provide a smooth surface for die holes 340 in FIGS. 6, 8, and 10 toreduce erratics from manufacturing processes such as bore marks, the dieholes 340 can undergo treatment by electron discharge machining (EDM)utilizing a wire that is circumferentially rotated about the die hole.This can enhance surface smoothness, improve uniformity of the die holegeometry, and controllably and uniformly increase the die hole diameter.Alternatively, high-velocity abrasive and polishing grits of uniformlyfine grain size can be passed through the die holes to effect improvedsmoothness within the die hole. Additionally, inserts (e.g., made from afluoropolymer, tungsten carbide, other ceramics, and the like) to reduceabrasion and adhesion can be placed into the lands of die holes 340.Other surface treatments for improvement of surface properties,enhancement of corrosion and abrasion resistance, and improvement ofwear can be used.

Referring once again to FIG. 5, the die 300 is coupled to transportfluid box 400 as shown in FIGS. 10 and 11, and detailed in FIGS. 12, 13a, 13 b, and 13 c. FIG. 10 illustrates a configuration of a one-piecetransport fluid box 400 that comprises a housing 402 to which isconnected inlet pipe 404 and outlet pipe 406, which have a similardiameter and geometry, are diametrically opposed to each other, and arecoupled to a rectangular, square, cylindrical or other geometricallyopen cutting chamber 408. The open cutting chamber 408 surrounds, and isof sufficient diameter to completely encompass, the die face 410(representationally equivalent to the surface of hardface 370 in FIGS.6, 8, and 9). Housing 402 has mounting flange 412 through which aplurality of mounting bolts 414 pass to sealingly attach the transportfluid box 400 and die 300 to diverter valve 84. Flange 416 on housing402 allows attachment to the pelletizer 900 (see FIG. 5) as is detailedbelow. Components that are free to rotate within the cutting chamber 408are described below.

Similarly, FIG. 11 illustrates a two-piece configuration of transportfluid 400 comprising a main body 450 with a housing 452 to which isconnected inlet pipe 454 and outlet pipe 456, which are of similardiameter and geometry, are diametrically opposed to each other, and arecoupled to a rectangular, square, cylindrical, or other geometricallyopen cutting chamber 458. The open cutting chamber 458 surrounds, and isof sufficient diameter to completely encompass, the die face 410(representationally equivalent to the surface of hardface 370 in FIGS.6, 8, and 9). Housing 452 has mounting flange 462 through which aplurality of mounting bolts or studs 464 pass. Mounting flange 462sealingly attaches to adapter ring 470 of comparable diameter, bothinside and outside dimensions, through which pass a plurality ofcountersink bolts 472. Mounting bolts or studs 464 and countersink bolts472 are preferably positioned in an alternating manner, and sealinglyattach the components the complete transport fluid box 400 and die 300to diverter valve 84. Flange 466 on housing 452 of the main body 450allows attachment to the pelletizer 900 (see FIG. 5) as is detailedbelow. Components that are free to rotate within the cutting chamber 408in FIG. 10 and/or cutting chamber 458 in FIG. 11 are described below.Separate attachment of the adapter ring 470 to and through the die 300allows the main body 450 to be removed for cleaning or maintenance whileleaving die body 300 sealingly attached to diverter valve 84.

An exploded view of the two-piece configuration of transport fluid box400 is illustrated in FIG. 12, with a complete assembly illustrated inFIG. 13. Reference numbers are retained to be consistent wherein similarparts have similar numbers in FIGS. 11, 12, and 13 a.

FIGS. 13 b and 13 c illustrate an alternative design for the transportfluid box inlet and outlet in that inlet 480 is fixedly attached to arectangular or square inlet tube 482 that taperingly increases along itslength as it approaches the housing 481 to which it is attachedlyconnected and within which is cutting chamber 484. Similarly, attachedto housing 481 and diametrically opposed to inlet tube 482 isrectangular or square outlet tube 486 that taperingly decreases alongits length to outlet 488 to which it is fixedly attached. Flange 483 andflange 485 in both FIGS. 13 b and 13 c compare in design and purpose toflanges 462 and 466 in FIG. 13 a.

FIGS. 13 a, 13 b, and 13 c illustrate the preferred diametricallyopposed inlets and outlets. Alternatively, the inlets, 454 and 480, andoutlets, 456 and 488, can be located at an angle from 20° to thepreferred 180° relative to, and defined by the position, of outlet toinlet, and can be opposingly or staggeringly attached to housing 481.Dimensions of the inlet and outlet can be the same or different, and theinlet and outlet can be similar or different in design. Preferably theinlet and outlet so identified are of similar dimension and design, andare diametrically opposed.

Returning to FIG. 12, for conventional surface treatments to reduceabrasion, erosion, corrosion, wear, and undesirable adhesion andsticture, the inner surface 1812 of flange 466 and the lumens 1818 ofinlet pipe 454 and outlet pipe 456 can be nitrided, carbonitrided,sintered, can undergo high velocity air and fuel modified thermaltreatments, and/or can be electrolytically plated. The exterior surface1814 and exposed surface 1816 of die body 320 can be treated similarly.It is understood that variations illustrated in FIGS. 10, 11, 12, 13 a,13 b, and 13 c can be treated similarly. Other surface treatments forimprovement of surface properties, enhancement of corrosion and abrasionresistance, improvement of wear, improvement of wear, and/or reductionof clumping, agglomeration, and/or sticture can be used as well.

For tacky materials, it is preferred to use a larger diameter inlet pipe404 and larger outlet pipe 406 (FIG. 10) or larger inlet pipe 454 andlarger outlet pipe 456 (FIGS. 12 and 13 a) or larger inlet tube 482 andlarger outlet tube 486 (FIGS. 13 b and 13 c) for transport fluid box 400than would be expected by those skilled in the art. The larger inletpipes or tubes occupy a larger portion of the respective housingsplacing them in closer proximity to the die face 410, FIGS. 10 and 11,and facilitate more direct access of the transport fluid entering thetransport fluid box 400 directly to the face of the die. The largeroutlet pipes or tubes provide more open area for the pellet/transportfluid slurry to be removed from the actual chamber 408 and 458 (FIGS. 10and 11, respectively) of the transport fluid box 400. The greater openarea also reduces the likelihood of pellet collisions potentiallyleading to agglomeration, adhesion, and sticture. The increaseddiameters of the inlets and outlets offer additional options regardingvolume in that the transport fluid flow rate, as one option, can remainthe same as that through the more typical size inlets and outlets, thusreducing the turbulence the pellets are subjected to in the transportfluid box 400. Alternatively, the transport fluid flow rate can beincreased proportionately to the increase in the diameter of the inletand outlet, thus increasing the effective volume of transport fluid inrelation to the number of pellets for the same tacky material throughputrate while maintaining the effective turbulence introduced atapproximately the same level as would be experienced with the lowerdiameter inlets and outlets. As a third alternative, the larger diameterinlets and outlets allow a higher transport fluid flow rate facilitatingboth a greater proportionate volume of transport fluid relative to thepellets, as well as providing higher velocity of that transport fluidinto and through the transport fluid box 400, effectively removing thepellets from the cutting chamber more quickly.

Alternatively, the respective inlet pipes can be of smaller diameterthan the outlet pipes. For tacky materials it is preferred not to havethe outlets smaller in diameter than the respective inlets as this leadsto more turbulence, increased likelihood of pellet collisions, andconstriction of the open area through which the pellets can leave thecutting chamber.

Once again returning to FIG. 5, pelletizer 900 is shown in thenon-operational open position. Coupled to the pelletizer is flow guide800, and cutter hub 600 with cutter blades 700. Upon operation of theequipment, pelletizer 900 is moved into position such that it can beattached to flange 416 of the one-piece configuration of transport fluidbox 400 or flange 466 on the main body 450 of the two-piececonfiguration of transport fluid box 400, as detailed in FIGS. 10 and11, respectively. Attachment is most preferably made using quickdisconnects, but can be through many mechanisms. In the operatingconfiguration, the cutter hub 600 and cutter blades 700 freely rotatewithin the cutting chamber 408 (FIG. 10) or 458 (FIG. 11). Details ofall illustrated components are contained within the ensuing discussions.

The pelletizer 900 is shown diagramatically in FIG. 14 and can bepositionally adjustable in terms of cutter hub 600 relative to die face410. FIG. 14 represents the pelletizer 900 in operational positionwherein it is sealingly attached via pelletizer flange 902 to transportfluid box flange 466, tightly held by removable quick disconnect clamp904, for example. Positional adjustment of the pelletizer can beachieved manually, using a spring-loaded mechanism, hydraulically,pneumatically, electromechanically, or the like, or by combinations ofthese mechanisms acting cumulatively in one direction or opposingly incounter-direction of forces applied to insure appropriateness ofposition as necessitated to achieve even wear, increased longevity,avoidance of undue extrusion leading to melt wrap around the cutter hubor the die face 410, and consistency of the pelletized product. Fortacky materials, manual and electromechanical adjustment of thepelletizer position is preferred. In a more preferred design, thehydraulic-pneumatic mechanism detailed in FIG. 14 is comprised of amotor 905, housing 910, and contains hydraulic cylinder 920 engagedlyattached to coupling 922. A rotor shaft 930 connects coupling 922 to thecutter hub 600 at the die face 410 and passes through thrust bearing 940and sealing mechanism and preferably a mechanical sealing mechanism 950in fluid contact with cutting chamber 458 of transport fluid box 400.Inlet pipe 454 and outlet pipe 456 indicate flow direction of fluids,preferably water, into the cutting chamber 458, admixture of fluids andpellets in the cutting chamber 458, and, subsequently, flow of thepellet slurry formed away from the cutter hub 600 as well as die face410 and out of the cutting chamber 458.

To increase fluid velocity through the cutting chamber 458, improvepellet quality, reduce freeze off, avoid wrapping of melt around dieface 410, generate or increase head pressure, and improve pelletgeometry, FIG. 15 illustrates a configuration in which an optional flowguide 800 can be positioned in the cutting chamber 458 to effectivelyreduce the fluid volume of that region. The die 300, transport fluid box400, and pelletizer 900, shown only partially, are positionally the sameas in FIG. 14. The hollow shaft rotor preferably is attached to cutterhub 600 in cutting chamber 458 with appropriate inlet pipe 454 andoutlet pipe 456 as previously described. The pelletizer 900 is sealinglyand removably attached to the transport fluid 400 through use of quickdisconnect clamp 904 on pelletizer flange 902 and transport fluid boxflange 466 as before. FIGS. 16 a and 16 b show two exemplaryconfigurations for flow guide 800, in which sections can be of similaror different segmental length having consistent outside diameter that isless than the diameter of cutting chamber 458 and can be varied inaccordance with the requisite diminution of volume desired in thatcutting chamber 458. Flow guide spacer sections 803 can be uniformcircumferentially and diametrically as indicated by the single spacer803 a, or multiple spacers 803 b and 803 c, but can vary in segmentallength and are not limited in number. To direct and/or restrict flow,flow directing segments 801 (e.g., shown as a single segment 801 a ormultiple segments 801 b, 801 c, and 801 d) are modified bylongitudinally extending grooves that are arcuate in transverseconfiguration with the deepest grooved section positioned proximal tothe cutter hub 600.

Continuing with FIG. 14, cutter hub 600 is attached by screwing onto thethreaded end of the rotor shaft 930 of pelletizer 900. The cutter hub600 can be rigidly mounted to the rotor shaft 930 and can contain anumber of cutter arms 610 in balanced proportion placedcircumferentially about the cutter hub 600 as illustrated in FIG. 17.Alternatively, the cutter hub 600 is flexibly attached to rotor shaft930 using an adapter 620 in which the adapter 620 is attachedly andthreadedly connected to rotor shaft 930. Adapter 620 has a partialspherical outer surface 622 matching a similar partial spherical innersurface bore 602 in the cutter hub 600. Diametrically opposed to, andrecessed into, the partial spherical inner surface bore 602 arelongitudinal recesses 605 that extend to the edge of the cutter hub 600,and into these recesses 605 fit ball 640. Similarly diametrical recesses626 for ball 640 are located on adapter 620, which is oriented such thatlongitudinal recess 605 and diametrical recess 626 align tointerlockingly affix balls 640 once adapter 620 is inserted orthogonallyinto position and rotated to a position parallel to cutter hub 600. Thisallows free oscillation of the cutter hub 600 about the diametricallypositioned balls 640 on adapter 620 to rotor shaft 930 that permitsrotational self-alignment of the cutter hub 600.

The cutter arms 610 and body of cutter hub 612 can be square orrectangular in cross-section as shown in FIG. 17, or can be morestreamlined for tacky materials to give an extended hexagonalcross-section as illustrated in FIG. 18 c. FIGS. 18 a and 18 b showsegments of streamline cutter hub 650. Cutter blades are fixedlyattached by screw or similar mechanism at flattened angular groove 614,shown in FIG. 17, or at flattened angular notch 652, shown in FIGS. 18 aand 18 b.

FIG. 19 illustrates various angularly inclined positions and shapes ofthe cutter blades 750. The blade angle 755 can vary from approximately0° to approximately 90° and greater, as seen in FIGS. 19 a, 19 b, and 19c, relative to die hard face 370, FIG. 10, with a blade angle 755 ofranging from approximately 20° to approximately 60° preferred, and amore preferred blade angle 755 of approximately 30° to approximately50°. The blade cutting edge 760 can be square, beveled, or angled, andcan be at a blade cutting angle 765 of 0° to 90°, preferably at a bladecutting angle 765 less than or equal to approximately 20% less than theblade angle 755, and more preferably approximately at a blade cuttingangle 765 less than or equal to approximately 15% less than the bladeangle 755. FIG. 19 d illustrates a portion of die face 410 and die hole340 across which passes cutter blade 750 with blade cutting edge 760passing rotationally across die hole 340 at a traverse angle 775 thatcan range from approximately 0° to approximate 55° and greater.Preferably the traverse angle 775 ranges from approximately 20° toapproximately 55°. Most preferably, for tacky materials, the preferredblade angle 755 ranges from approximately 30° to approximately 50° withthe blade cutting angle 765 preferably less than 15% smaller than thepreferred blade angle 755 such that the blade cutting edge 760 passesacross die face 410 at a traverse angle ranging from approximately 20°to approximately 55°.

Alternatively, is a reduced thickness blade 770, as illustrated in FIG.19 c, that can be similarly attached, similarly angled, and withcomparable blade cutting angles and preferences as described above. Thecutter blade 750 and reduced thickness blade can also be reduced inlength such that the upper end of the blade is of sufficient length toprovide attachment by screw 748 but does not extend significantly abovethe uppermost surface of cutter arms 610.

The cutter blade 750 and reduced thickness blade 770 can be formed fromtool steel, stainless steel, nickel and nickel alloys, metal-ceramiccomposites, ceramics, metal or metal carbide composites, carbides,vanadium hardened steel, suitably hardened plastic, or other comparablydurable material, and can be further annealed and hardened as is wellknown to those skilled in the art. Wear-resistance, corrosionresistance, durability, wear lifetime, chemical resistance, and abrasionresistance are some of the important concepts influencing the utility ofa particular blade relative to the formulation being pelletized. Bladedimensions of length, width, and thickness as well as number of bladesused relationally with cutter hub design are not limited within thescope of the present invention.

Additionally, surface treatments to reduce abrasion, erosion, corrosion,wear, and undesirable adhesion and sticture can be applied to variouscomponents of the pelletizing section 6 (FIG. 1) as disclosed incommonly-assigned International Patent Application Publication No. WO2009/059020, which is incorporated by reference in its entirety as iffully set forth below. Such treatments can include nitriding,carbonitriding, sintering, high velocity air and fuel modified thermaltreatments, and electrolytic plating. In addition, flame spray, thermalspray, plasma treatment, electroless nickel dispersion treatments, andelectrolytic plasma treatments, can be utilized.

Other surface treatments for improvement of surface properties,enhancement of corrosion and abrasion resistance, improvement of wear,and/or reduction of clumping, agglomeration, and/or sticture can be usedtoo.

FIG. 5 illustrates the relative position of the bypass loop 550.Transport fluids, including water, for use in the bypass loop 550 andpellet transportation is obtained from reservoir 1600 or other sources,and is transported toward the transport fluid box 400 through pump 500that can be of a design and/or configuration to provide sufficient fluidflow into and through the optional heat exchanger 520 and transport pipe530 to and into bypass loop 550. The heat exchanger 520 similarly can beof a design of suitable capacity to maintain the temperature of thewater or other transport fluid at a temperature appropriately suitableto maintain the temperature of the pellets being formed such that pelletgeometry, throughput, and pellet quality are satisfactory withouttailing, and where wrap-around of molten plastic on the cutting face,agglomeration of pellets, cavitation, and/or accumulation of pellets inthe transport fluid box or waterbox are maximally avoided. Temperaturesand flow rates as well as composition of the transport fluid will varywith the material or formulation being processed. Transport fluidtemperatures are preferably maintained at least approximately 20° C.below the melting temperature of the polymer, and preferably aremaintained at a temperature of at least approximately 30° C. toapproximately 100° C. below the melt temperature. For tacky materialsthe transport fluid temperatures preferably are maintained at atemperature ranging from approximately 0° C. to approximately 35° C.

Additionally processing aids, flow modifiers, surface modifiers,coatings, surface treatments including antistatic agents and variousadditives known to those skilled in the art can be accommodated in thetransport fluid. Piping, valving, and bypass components should be ofsuitable construction to withstand the temperature, chemicalcomposition, abrasivity, corrosivity, and/or any pressure requisite tothe proper transport of the pellet-transport fluid mixture. Any pressurerequired by the system is determined by the vertical and horizontaltransport distance, pressure level needed to suppress unwantedvolatilization of components or premature expansion, pellet-transportfluid slurry flow through valving, coarse screening, ancillary processand/or monitoring equipment. Pellet-to-transport fluid ratios shouldsimilarly be of varying proportions to be satisfactorily effective ineliminating or alleviating the above-mention complicating circumstances(e.g., pellet accumulation, flow blockage or obstruction, andagglomeration). Piping diameter and distances required are determined bythe material throughput, thus the flow rate and pellet-to-transportfluid ratio, and time required to achieve an appropriate level ofcooling and/or solidification of the pellets to avoid undesirablevolatilization and/or premature expansion. Valving, gauges, or otherprocessing and monitoring equipment should be of sufficient flow andpressure rating as well as of sufficient throughpass diameter to avoidundue blockage, obstruction, or otherwise alter the process leading toadditional and undesirable pressure generation or process occlusion.Transport fluid and additive composition should be compatible with thecomponents of the pellet formulation and should not be readily absorbedinto or adsorbed onto any of the components in that formulation. Excesstransport fluid and/or additives should be readily removable from thepellets by such methods as rinsing, aspiration, evaporation, dewatering,solvent removal, filtration, or a similar technique understood by thoseskilled in the art.

Pump 500 and heat exchanger 520 in FIG. 5 can be prone to abrasion,erosion, corrosion, and wear as well, particularly from by-products ofthe pelletization process, and components can optionally be surfacetreated utilizing nitriding, carbonitriding, sintering, high velocityair and fuel modified thermal treatments, and electrolytic plating. Inaddition, flame spray, thermal spray, plasma treatment, electrolessnickel dispersion treatments, and electrolytic plasma treatments, singlyand in combinations thereof can be utilized.

The standard bypass loop 550, as illustrated in FIG. 20, allows thetransport fluid, preferably water, from inlet pipe 530 to enterthree-way valve 555 and be redirected into the bypass flow or toward thetransport fluid box 400. To bypass the transport fluid box 400, thetransport fluid is directed by three-way valve 555 into and throughbypass pipe 565 into outlet pipe 570. To achieve this, blocking valve575 is closed. Alternatively, to allow water to flow to and through thetransport fluid box 400, the three-way valve 555 is directed to allowflow into and through pipe 560 and into pipe 580 with blocking valve 575open and with drain valve 590 closed. Transport fluid proceeds into andthrough transport fluid box 400 and transports pellets into and throughsight glass 585 through blocking valve 575 and into outlet pipe 570 fordown-stream processing as described below. To drain the system and allowcleaning or maintenance of the transport fluid box 400 or die hardface370, or to replace any of the die 320 components, three-way valve 555directs flow into and through pipe 565 and into outlet pipe 570. Withblocking valve 575 now closed and drain valve 590 open, the transportfluid remaining entrapped below 575, in components 585, 400, 560, and580 drains out drain 595 for recycling or disposal.

Referring once again to FIG. 5, the pellets that are sufficientlysolidified for processing are transported to the dewatering/dryingsection 8 (FIG. 1) via pipe 1270 to and through an agglomeratecatcher/defluidizing unit 1300 and into the drying unit 1400,subsequently exiting the dryer for additional processing as describedbelow. These pipes can be manufactured to form short radius and longradius right angles, or alternatively can be bent to form short radiusand long radius sweep angles or curves, which are used preferential forapplications involving tacky materials to reduce the likelihood ofadhesion, sticture, and agglomeration. Without intending to be bound bytheory, it is anticipated that induced stresses can be introduced bysuch manipulations potentially leading to increased likelihood ofwear-related failures due to abrasion, erosion, and/or corrosion, forexample. Thus abrasion, erosion, corrosion, wear, and undesirableadhesion and sticture can be problematic in transport piping andtreatments including nitriding, carbonitriding, sintering, electrolyticplating, electroless plating, thermal hardening, plasma treatments,extrusion, rotational molding or “rotolining,” slush molding, andcombinations thereof can be utilized to improve the resistance towear-related processes and to reduce adhesion and sticture. Othersurface treatments for improvement of surface properties, enhancement ofcorrosion and abrasion resistance, improvement of wear, and/or reductionof clumping, agglomeration, and/or sticture can be used as well.

Turning now to FIG. 21, the pipe 1270 discharges the pellets and fluidslurry or concentrated slurry into an agglomerate catcher 1300 thatcatches, removes, and discharges pellet agglomerates through a dischargechute 1304. The agglomerate catcher 1300 includes an angled round baragglomerate removal grid 1310, perforated plate, or screen that permitspassage of fluid and pellets through discharge outlet 1302 but collectsadhered, clumped, or otherwise agglomerated pellets and directs themtoward the discharge chute 1304.

In an alternative embodiment, FIG. 22 illustrates an overflowagglomerate catcher assembly 1320 that is comprised of a housing 1322 ofany geometric configuration, that is preferably rectangular in shape andtapers downwardly and inwardly to form outlet 1324. Hingedly attached tothe front of housing 1322 is access door 1326 with handle 1328. The doorcan be hinged at the side or at the top as space and ease of accessallows. The pellet slurry enters from pipe 1270 through inlet 1330 andpasses over agglomerate removal grid 1310. Attached, preferably bybolting, to the back of housing 1322 and covering an overflow opening isoverflow housing 1334. The overflow opening can optionally be covered bya foraminous membrane device as described in detail below. Theforaminous membrane device can be removably attached at the juncture1336 between the housing 1322 and the overflow housing 1334 as bybolting or insertion into a slotted groove for ease of removal to clean.Alternatively, the screening device can be fixedly attached, as bywelding, to the juncture 1336. The embodiment is preferable formaterials prone to high levels of agglomeration formation, particularlysticky or tacky materials, such that build-up of agglomerates can betolerated wherein the flow of the pellet slurry is not obstructed by thebuild-up. The choice of the screening device is of particular importanceto minimize clogging during an overflow situation. This embodiment isfurther preferable for low fluid temperature processing and manualoperations.

The agglomerate removal grids 1310 in FIGS. 21 and 22 can be at manyangles of inclination 1340 that can range from approximately 0° togreater than 50° as measured from a horizontal plane that transects thelowest point of the agglomerate removal grid (indicated by the dottedline 1342 in FIGS. 21 and 22). Preferably the angle of inclination 1340ranges from approximately 20° to greater than 50°, more preferably fromapproximately 40° to greater than 50° and most preferably is greaterthan 50° as described. The lower angle of inclination is particularlyuseful for manual low fluid temperature processes to allow ease ofremoval from accumulating agglomerates. As the process moves from manualto automatic operation, the angle of inclination is favorably raised tominimize the need for operator activity. Thus in high volume processesand/or high temperature processes, the angle of inclination greater than50° is most preferable to allow the accumulation of agglomerates topurge itself upon opening of the gate 1344, as exemplified in FIG. 21,without need of assistance from an operator, or manually as accessedthrough door 1346. The subsequent release of the agglomerates into theagglomerate overflow housing 1304 and through the outlet 1348 allowsremote collection and/or transport of the accumulated agglomerates awayfrom the area of operation. Subsequently, outlet 1348 can be connectedto a waste bin, a recycle bin, and other storage and transportmechanisms as are known to those skilled in the art. Additional detailsof the agglomerate catcher 1300 and overflow agglomerate catcherassembly 1320 designs and construction are disclosed incommonly-assigned International Patent Application Publication No. WO2010/028074, which is incorporated herein by reference in its entiretyas if fully set forth below.

Surface treatments to reduce abrasion, erosion, corrosion, wear, andundesirable adhesion and sticture, can be applied to various componentsof agglomerate catcher 1300 (FIG. 21) and overflow agglomerate catcherassembly 1320 (FIG. 22). Preferably, the agglomerate removal grid 1310and inside of housing 1322 are surface treated for use in processingtacky materials. Such treatments can include nitriding, carbonitriding,sintering, high velocity air and fuel modified thermal treatments, andelectrolytic plating. In addition, flame spray, thermal spray, plasmatreatment, electroless nickel dispersion treatments, and/or electrolyticplasma treatments, can be utilized.

The pellets and fluid slurry then pass from the discharge outlet 1302,FIG. 21 or outlet 1324, FIG. 22, into a defluidizer 1350, FIG. 23, thatcan include at least one vertical or horizontal defluidizing foraminousmembrane 1355 containing one or more baffles 1360 and/or an inclinedforaminous membrane 1365, angular or cylindrical, that enables fluid topass downwardly into a fines removal screen 1605 and therethrough to thewater reservoir 1600 (FIGS. 5 and 25). Preferably for tacky materials,baffles 1360 can be omitted to prevent adhesion, sticture, andagglomeration of the pellets. Similarly, the inclined foraminousmembrane 1365 can be blocked at least partially and preferably iscompletely blocked to prevent adhesion, sticture, and agglomeration. Thepellets that still retain moisture on their surfaces are discharged fromdefluidizer 1350 into the lower end of the dryer 1400 at a slurry inlet1405, FIGS. 23 and 24.

The dryer 1400, illustrated in FIG. 23, can be of many types forachieving a controlled level of moisture for materials that can beflake-shaped, globular, spherical, cylindrical, or other geometricshapes. It can be achieved, for example, by filtration, centrifugaldrying, forced or heated air convection or a fluidized bed, and ispreferably a centrifugal dryer 1400.

As illustrated in FIGS. 23 and 24, the dryer 1400 includes but is notlimited to a generally cylindrical housing 1410 having a verticallyoriented generally cylindrical screen 1500 mounted on a cylindricalscreen support 1415 at the base of the screen, and a cylindrical screensupport 1420 at the top of the screen. The screen 1500 is thuspositioned concentrically within the housing 1410 in radially spacedrelation from the inside wall of the housing.

A vertical rotor 1425 is mounted for rotation within the screen 1500 andis rotatably driven by a motor 1430 that can be mounted at and/orconnected to the base of the dryer (FIG. 23) or at the top of the dryerand is preferably mounted atop the upper end of the dryer, FIG. 24. Themotor 1430 is connected to the rotor 1425 by a drive connection 1435 andthrough a bearing 1440 connected with the upper end of the housing. Theconnection 1445 and bearing 1440 support the rotor 1425 and guide therotational movement of the upper end of the rotor. The slurry inlet 1405is in communication with the lower end of the screen 1500 and rotor 1425through the lower screen support section 1450 at connection 1448, andthe upper end of the housing and rotor is in communication with a driedpellet discharge chute 1460 through a connection in the upper screensupport section 1455 at the upper end of the housing. A diverter plate1465 in optional outlet pipe 1467 can divert dried pellets throughoutlet 1470 or outlet 1475.

The housing 1410 is of sectional construction, and connected at aflanged coupling at a lower end portion of the dryer and a flangedcoupling at the upper end portion of the dryer. The uppermost flangecoupling is connected to a top plate 1480 that supports bearingstructure 1440 and drive connection 1435 that are enclosed by a housingor guard 1437. A coupling 1432 atop the housing 1437 supports the motor1430 and maintains all of the components in assembled relation.

The lower end of the housing 1410 is connected to a bottom plate 1412 ontop of a water tank or reservoir 1600 by a flange connection 1610 asillustrated in FIG. 25. Apertures 1612 communicate the lower end of thedryer housing with the reservoir 1600 for discharge of fluid from thehousing 1410 into the reservoir 1600 as the surface moisture is removedfrom the pellets. This removal is achieved by action of the rotor thatelevates the pellets and imparts centrifugal forces to the pellets sothat impact against the interior of the screen 1500 will remove moisturefrom the pellets with such moisture passing through the screen andultimately into the reservoir 1600.

The optional self-cleaning structure of the dryer 1400 includes aplurality of spray nozzles or spray head assemblies 1702 supportedbetween the interior of the housing 1410 and the exterior of the screen1500 as illustrated in FIG. 24. The spray nozzle assembly 1702 issupported at the end of spray pipes 1700 extending upwardly through topplate 1480 at the upper end of the housing with the upper ends 1704 ofthe spray pipes 1700 being exposed. Hoses or lines 1706 feed highpressure fluid, preferably water at a flow rate of at leastapproximately 40 gallons per minute (gpm), and preferably about 60 gpmto about 80 gpm, and more preferably at 80 gpm or higher to the spraynozzles 1702. The hoses 1706 can optionally feed off a single manifoldmounted on the dryer 1400.

There are preferably at least three spray head nozzle assemblies 1702and related spray pipes 1700 and lines 1706. The spray head nozzleassembly 1702 and pipes 1700 are oriented in circumferentially spacedrelation peripherally of the screen 1500 and oriented in staggeredvertical relation so that pressurized fluid discharged from the sprayhead nozzles 1702 will contact and clean the screen 1500, inside andout, as well as the interior of the housing 1410. Thus, collectedpellets that have accumulated or lodged in hang-up points or areasbetween the outside surface of the screen 1500 and inside wall of thehousing 1410 are flushed through apertures 1612 into the reservoir 1600,FIG. 28. Similarly, leftover pellets inside the screen 1500 and outsidethe rotor 1425 are flushed out of the dryer and will not contaminate orbecome mixed with pellets passing through the dryer during a subsequentdrying cycle in that a different type pellet is dried.

The region between the screen support section 1450 at the lower end ofthe dryer and the inner wall of the housing 1410 includes flat areas atthe port openings and seams that connect the components of the dryerhousing together. The high pressure water from the spray head nozzleassembly 1702 effectively rinses this region as well. The base screensupport section 1450 is attached to the bottom plate 1412 of the housing1410 and reservoir 1600 by screws or other fasteners to secure thehousing and screen to the reservoir 1600. The base screen supportsection 1450 is in the form of a tub or basin as shown in FIG. 25.Alternatively, in other dryers the base screen support section 1450 canbe in the form of an inverted tub or inverted base.

The rotor 1425 includes a substantially tubular member 1427 providedwith inclined rotor blades 1485 thereon for lifting and elevating thepellets, and subsequently impacting them against the screen 1500. Fortacky materials, it is preferable that the inclined rotor blades in atleast a portion of the upper half of the dryer are narrower in theirwidth as compared to the width of similar blades in the lower half ofthe dryer. The width being considered is the dimension across the bladeas measured from the juncture with the rotor to the most distal parallelor near-parallel edge of the blade. When the uppermost row of blades isoriented perpendicularly from the rotor as are often identified as“kickers,” it is preferable that these also be reduced in dimension oftheir width similarly defined. More preferably the uppermost rows ofblades including the row of kickers are of the same reduced width foruse with tacky materials. The reduction in width of rotor blades and/orkickers is at least approximately 10% less than the rotor blades inlower portions of the dryer, more preferably is at least approximately20% less than the width of rotor blades in lower portions of the dryer,and most preferably is at least 30% narrower than the width of rotorblades in lower portions of the dryer.

A hollow shaft 1432 extends through the rotor 1425 in concentric spacedrelation to the tubular member 1427 forming the rotor. The hollow shaftguides the lower end of the rotor as it extends through an opening 1482in a guide bushing 1488 at the lower end of the rotor 1425, as well asaligned openings in bottom plate 1412 and the top wall of the reservoir1600, respectively. A rotary coupling 1490 is connected to the hollowshaft 1432 and to a source of fluid pressure, preferably air, throughhose or line 1492 to pressurize the interior of the hollow shaft 1432.

The hollow shaft 1432 includes apertures to communicate the shaft 1432with the interior of the hollow rotor member 1427. These holes introducethe pressurized fluid into the interior of the rotor 1425. The rotor1425 in turn has apertures in the bottom wall that communicate thebottom end of the rotor 1425 with the interior of the base or tubsection 1450 to enable the lower end of the rotor 1425 and the tubsection 1450 to be cleaned. Pellets flushed from the rotor and insidescreen 1500 are discharged preferentially through the dried pelletoutlet chute 1460.

The top of the rotor 1425 inside top section 1455 is also a hang-uppoint and subjected to high pressure fluid, preferably, air, to dislodgeaccumulated pellets. As shown in FIG. 25, a nozzle 1710 directs the highpressure air across the top of the rotor 1425 to drive accumulatedpellets out of the top section and preferentially into the pellet outletchute 1460. The nozzle 1710 is fed by an air hose or line that extendsthrough top plate 1480 and is connected to a high pressure air source.

In addition to hang-up points or areas occurring in the dryer structure,the agglomerate catcher 1300 can also be cleaned by a separate pipe orhose 1720 controlled by a solenoid valve that directs high pressurefluid onto the pellet contact side of the angled agglomerate removalgrid 1310 to clean off agglomerates that are then discharged through thedischarge tube or chute 1305.

A hose and nozzle supply bursts of air to discharge chute or pipe 1460in a direction such that it cleans the top of the rotor 1425 and thepellet discharge outlet 1460. The air discharge blows pellets past pipeconnections and the diverter plate 1465 in outlet pipe 1467 fordischarge of dried pellets out of the dryer.

In other dryers, the rotor 1425 can be square, round, hexagonal,octagonal, or other shape in cross-section. Rotors can also be of solidconstruction as disclosed in commonly-assigned International PatentApplication Publication No. WO 2010/028074, which is incorporated hereinby reference in its entirety as if fully set forth below.

Blower 1760 in FIG. 5 is prone to abrasion, erosion, corrosion, and wearfrom by-products of the pelletization process as well as from the impactand/or adhesion of pellets on the surface of blower components, and canoptionally be surface treated, for example, utilizing nitriding,carbonitriding, sintering, high velocity air and fuel modified thermaltreatments, and electrolytic plating. In addition, flame spray, thermalspray, plasma treatment, electroless nickel dispersion treatments, andelectrolytic plasma treatments can be utilized individually or incombination.

The screens for the process can include one or more optional horizontalor vertical dewatering screens 1355, inclined defluidizing screen 1365,port screens 1595, and/or one or more cylindrically attachable screens1500, as illustrated in FIG. 26. The size, composition, and dimensionsof the screens should accommodate the pellets being generated and can beperforated, punched, pierced, woven, or of another configuration knownto those skilled in the art, and can be the same or different inconstruction, composition, and style. As the pellet size decreases indiameter, preferably the screens will be composed of two or more layersthat can be of similar or different composition, design, and size. Thescreens are fixedly attached by latches, clamps, bolts, and any otherappropriate mechanism.

The screens 1500 are preferably of suitably flexible construction as tobe circumferentially placed around the dryer 1400 and rotor 1425, andcan optionally be embossed and/or fitted with deflector bars (not shown)that are bolted in placed effectively segmentalizing the screen areainto approximately equal areas as is known to one skilled in the art.Preferably, screens 1500 are formed from at least one layer thataccomplishes the effective drying of the pellets.

The at least one layer screen 1500 can be composed of molded plastic orwire-reinforced plastic and compositionally can be polyethylene,polypropylene, polyester, polyamide or nylon, polyvinyl chloride,polyurethane, or similarly inert material that capably maintains itsstructural integrity under chemical and physical conditions anticipatedin the operation of the centrifugal pellet dryers. Preferably, thescreen 1500 is a metal plate of suitable thickness to maintain thestructural integrity of the overall screen assembly and flexible enoughto be contoured, exemplarily cylindrically, to fit tightly andpositionally in the appropriate centrifugal pellet dryer. The metalplate is preferably 18 gauge to 24 gauge, and most preferably is 18 to20 gauge in thickness. The plate can be formed from aluminum, copper,steel, stainless steel, nickel steel alloy, or similarly non-reactivematerial that is inert to the components of the drying process.Preferably, the plate is formed from stainless steel, and mostpreferably from Grade 304 or Grade 316 stainless steel, including lowcarbon grades as necessitated environmentally by the chemical processesundergoing the drying operation.

The metal plate can be pierced, punched, perforated, or slotted to formopenings that can be round, oval, square, rectangular, triangular,polygonal, or other dimensionally equivalent structure to provide openareas for separation and subsequent drying. Preferably, the openings areround perforations and geometrically staggered to provide the maximumopen area while retaining the structural integrity of the outer supportscreen. Most preferred are round perforations having a diameter of atleast approximately 0.075 inches (approximately 1.9 mm) that arestaggered to achieve an open area of approximately 40% or more.

Alternatively, the screen 1500 can be an assembled structure or screencomposed of wires, rods, or bars, stacked angularly or orthogonally, orinterwoven, and welded, brazed, resistance welded or otherwisepermanently adhered in position. The wires, rods, or bars can be plasticor wire-reinforced plastic compositionally similar to the molded plasticdescribed above or can be metal, similarly and compositionallydelineated as above and can be geometrically round, oval, square,rectangular, triangular or wedge-shaped, polygonal or structurallysimilar. The wires, rods, or bars across the width or warp of the screencan be the same as or different dimensionally as the wires, rods, orbars longitudinally contained as the weft, shute, or otherwise known tothose skilled in the art.

Preferably the wires, rods, or bars are a minimum of approximately 0.020inches (approximately 0.5 mm) in the narrowest dimension, morepreferably are at least approximately 0.030 inches (approximately 0.76mm) in the narrowest dimension, and most preferably are approximately0.047 inches (approximately 1.2 mm) in the narrowest dimension. Openareas are dimensionally dependent on the proximal placement of adjacentstructural elements and are positionally placed so as to maintain apercent open area of at least approximately 30%, more preferably aboveapproximately 40%, and most preferably approximately 50% or greater.

For particularly tacky materials, relative to the drying portion of theprocess, at least the lowermost screen section can be replaced orpartially replaced by a suitably flexible blank without perforation oropen area. This serves the purpose of transporting the pellets in theresidual transport fluid further up into the mid-portions of thecentrifugal dryer effectively reducing agglomeration, sticture and thelikely blockage of the lower portions of the dryer. This blank screencan be of similar or different composition to that of the screen portionfor which it serves as replacement and is consistent dimensionally withthose screens or screen portions as described above.

Returning to FIG. 5, pellets discharged from dryer 1400 pass into thepellet diverting section 10 (FIG. 1) into and through pellet dischargechute 1460, and optionally can be deflected through outlet 1475 asdetailed above, or can pass through outlet 1470 into and throughbagging/packaging section 12 (FIGS. 1 and 5). Attached to outlet 1470 isa symmetrically inverted and “Y”-shaped pellet diverter assembly 1600 asdisclosed in commonly-assigned International Patent Application NumberPCT/US10/25255 referenced above, and illustrated in FIGS. 27 a and b.Pellet diverter inlet 1602 is coupled to outlet 1470 from FIG. 24 eitherdirectly or in addition to an appropriate extension pipe. The pelletsenter the pellet diverter assembly 1600 through inlet 1602 into andthrough inlet pipe 1618, and are directed by diverter flap 1608 toeither outlet chute 1604 or outlet chute 1606 which are symmetricallypositioned about plane 1620 at preferred angles 1622 and 1624 ofapproximately 30°. Operation of diverter flap 1608 can be accomplishedmanually, electronically, hydraulically, and/or automatically includingthe optional use of a programmable logic controller (PLC). Theabove-referenced International Patent Application discloses thepreferential use of a pneumatic actuator 1614 that is operated by anelectronically controlled solenoid valve 1616 directed by a PLC. Thespeed at which the diverter flap 1608 moves can be further regulatedthrough use of needle valves to minimize the possibility of trappingpellets between the diverter flap 1608 and the inside walls of thepellet diverter assembly 1600. In turn, each outlet chute (1604, 1606)is attachedly connected to a bagging unit as described hereinbelow.

FIGS. 28 and 29 illustrate another embodiment of a pellet diverterassembly 1700, with pellet inlet 1702 through which pellets pass intoand through inlet tube 1704 into and through pellet chutes 1706 and 1708disposed, preferably symmetrically, about midplane 1710 to form therespective angles 1712 and 1714. Angles 1712 and 1714 can be orientedless than 90° from midplane 1710 and are preferably approximately 15° toapproximately 60° from the midplane. As above, angles 1712 and 1714 arepreferably symmetrically disposed about midplane 1710 at 30°. Operationof diverter flap 1716 can be accomplished manually, electronically,hydraulically, automatically, and/or electromechanically, including theoptional use of a PLC. FIG. 29 illustrates a configuration in which anelectromechanical linear actuator control device 1718 (e.g., a stepperor servo-motor) connects into an through gear reduction box 1720 tocoupling 1722. Solid shaft 1728 is threadingly engaged to the linearactuator control device 1718 through coupling 1722, and is positionallymaintained by bearings, preferably roller bearings, 1724 and 1726.Diverter flap 1716 is coupled to solid shaft 1728 and is positionallymonitored by visual indication or optionally by limit or proximityswitches 1730. Use of linear actuation, permits variable speed finecontrol of the opening and closing of diverter flap 1716 so as to avoidthe accidental entrapment of pellets between diverter flap 1716 and theinner wall of the pellet diverter assembly 1700.

To better accommodate the dimensionally continuous open flow area of thetransition from the inlet tube 1704 into pellet chutes 1706 and 1708,housing offset 1734, FIG. 28, facilitates the movement of the edge ofthe diverter flap 1716 past the juncture. The rate at which the diverterflap 1716 moves across the gap and approaches the housing offset 1734can be varied such that pellets are not trapped between the diverterflap 1716 and the inner wall of the pellet diverter assembly 1700 suchthat the rate is preferably slowed once the diverter flap 1716 is inclose proximity to the housing offset 1734. The housing offset 1734additionally provides an extended area for the motion of the diverterflap 1716 to discontinue. Thus, pellet diverter assembly 1700 preventsabrupt closure of the diverter flap 1716 with the inner surface.Additionally, perforated ventilation shield 1732, FIG. 29, allowsambient circulation of air about coupling 1722 to insure proper coolingas required.

Pellets pass through the pellet diverting section 10 into thebagging/packaging section 12 according to FIG. 1. Conventional baggingunits of any design can be connected to at least one pellet chute 1706or 1708. For continuous operation at least two bagging machines must beattached, one to each of pellet chutes 1706 and 1708. The pellet chutes,as well as the bagging machines, can be the same or different and thesize of the bag or packaging made on the different bagging machines canbe the same or different. Preferably, the pellet chutes 1706 and 1708are dimensionally the same and the bagging machines are the same. Pelletchute extensions can be coupled to at least one of the pellet chutes.The length of any pellet chute extensions, the number of baggingmachines, and the multiplicity of the pellet chutes that can be used islimited by the momentum of the pellets freely falling from the pelletdischarge outlet 1460 of dryer 1400 (FIG. 24).

The bagging machine(s) can be of any design as is known to those skilledin the art. Preferably the bagging machine forms the bag verticallyallowing the pellets to fill the bag through a forming tube andultimately seals and releases the bagged/packaged product. Asillustrated in FIG. 30, pellets traverse through pellet chute 1706, forexample, and freely fall into and through optional pellet chuteextensions into collecting funnel 1802 and are thus directed into andthrough forming tube 1804. By way of example, the bagging material isfed and/or pulled under tension as a sheet through tension rollers overforming collar 1806 as indicated by arrows 1808 and around forming tube1804. The edges of the bagging material are sealed along at least aportion of the length of the forming tube 1804. The now tubular baggingmaterial continues to be fed and/or pulled along the length of theforming tube 1804 extending past the lowermost edge of forming tube 1804to form a freely suspended tube. The length of the tube thus formed isadjusted according to the need of the size of the bag and/or thequantity of the packaged material needed. The tube is sealed across itsdiameter, preferably horizontally and perpendicularly to the length ofthe tube. Such sealing, thermal or otherwise, can be simultaneous withor independent of the sealing of a predecessor bag as is known to thoseskilled in the art. Where the top of one bag is sealed to form thecompleted package simultaneously with sealing the bottom edge of thenext sequential bag, separation of those bags can be achieved by theactual sealing mechanism and is preferentially achieved by a physicalcut made across and through the fully sealed area. Such separation canbe done at the time of sealing or can be accomplished as a part of anysubsequent downstream processing as needed. Post-processing can includeadditional packaging, labeling, assembly into boxes, and the likewithout intending to be limited in scope or in function.

Collecting funnel 1802 in FIG. 30 can be coupled to pellet chute 1706 orcan be separated such that the pellets fall therebetween. Collectingfunnel 1802 and forming tube 1804 can be of any material of constructionincluding plastic or metal compatible with the composition of thematerial being processed and capable of fulfilling the equipmentoperating requirements of the bagging process and are preferablystainless steel.

The quantity of material charged into the bag is dependent on theproduction rate for the pellets, the length of time the diverter flap1716 is positioned to direct flow of the pellets into and through therespective pellet chutes 1706 and 1708, FIG. 28, as well as the size ofthe bag. Operation of the bagging process including control of thebagging machine(s) and any automated controlling device for the diverterflap 1716, can be controlled by at least one PLC. Feedback mechanisms,preferably weight-measuring devices, can be integrated with the baggingprocess and under PLC control such that the timing of the diverter flap1716 can be modified to maintain reproducibility as needed in the finalbagged/packaged product being delivered.

The bag can be purged by conventional means with inert gas (e.g., air,carbon dioxide, nitrogen, and the like) or can be evacuated. Addition orreduction of gas and other volatiles can be achieved during thebag-filling process by introduction into the form filling tube 1804and/or collecting funnel 1802 or can be done just prior to the sealingof the bag. Similarly, the bag can contain perforations, also byconventional means, dimensioned such that the pellets and any othermaterials contained in the bag cannot leak out.

For particularly problematic tacky materials, pellets can be coated withtack-reducing powders prior to the bagging process. This can be done byintroducing the appropriate powdered material as, for example, byfeeding it into at least one of the components of the pellet divertingsection 10 in FIGS. 1 and 5. Powders so introduced can include silica,calcium carbonate, clay, wax, microcrystalline wax, polymers, talc, flyash, graphite, limestone, grit, sulfur, and the like. The powder fallsfreely and admixes with the similarly freely-falling tacky materialpellets adhering to the surface as it traverses through the assembly.Extra powder can be bagged and/or packaged or can be removed ifnecessary as by vacuum for example.

Bagging materials can include paper, cellulosics, polymers, and the likethat can be removed from the pelleted contents for later application.Preferably, the bagging materials are compatible with the pelletedcontents and are included along with the contents in the appropriateapplications. Materials that can be used for bagging can includeethylene-based polymers, such as ethylene/vinyl acetate, acrylicpolymers, ethylene acrylate, ethylene methacrylate, ethylene methylacrylate, ethylene methyl methacrylate, polyethylene including linearlow density, ultralow density, low density, medium density, and highdensity, polyamides, polybutadiene rubber, polyesters, polyethyleneterephthalate, polybutylene terephthalate, polycarbonates, polyolefins,polypropylene, polyacrylamides, polyacrylonitrile, polymethylpentene,polyphenylene sulfide, polyurethanes, styreneacrylonitrile,acrylonitrilebutadienestyrene, styrene butadiene rubbers, polyphenylenesulfide, polyvinyl halides, polyvinylidene dihalides, silicones,fluoropolymers, rubber-modified polymers, and blends, copolymers, andterpolymers thereof. Compatible materials used for bagging as usedherein should not alter the formulation of the contents detrimentallyand are capable of being mixed and/or dissolved uniformly and completelywith the contents of the bag in the final application. Compatiblematerials for use in bagging are disclosed in reissued U.S. Pat. No. RE36,177, which is incorporated by reference in its entirety as if fullyset forth below.

The bagging material can range in thickness from approximately 0.012inches (approximately 0.30 mm) to approximately 0.0005 inches(approximately 0.0127 mm), and preferably ranges from approximately0.0045 inches (approximately 0.114 mm) to approximately 0.00075 inches(approximately 0.019 mm). Most preferably, the bagging material canrange in thickness from approximately 0.002 inches (approximately 0.05mm) to approximately 0.0008 inches (approximately 0.02 mm). One or morelayers of bagging materials can be used, and the bagging material(s) cancontain additives and release agents, including anti-foaming agents,anti-oxidants, stabilizers, and the like. For compatible baggingmaterials the additives contained therein must similarly be compatibleas described hereinabove.

It should be noted that the surface treatments as specifically appliedto the inside of the agglomerate catcher, the agglomerate removal grid,the inside of the dryer housing and especially the upper portion of thedryer housing, as well as the components of the pellet diverting sectionand the funnel and forming tube of the bagging section describedhereinabove are preferentially at least two layers such that one layeris comprised of a highly wear-resistant material that is applied so asto confer a rough and highly textured surface over which is thenuniformly coated a polymeric material that only partially fills thetexturing of the wear-resistant material and provides an additionalnon-stick surface to prevent undesirable adhesion, sticture, andagglomeration of pellets as they are transported therethrough. Mostpreferably the wear-resistant component is ceramic and the non-stickpolymeric material is silicone, fluoropolymers, and combinations,thereof.

What is claimed is:
 1. A system for continuously bagging tackymaterials, the system comprising: a feeding section configured toreceive a material, wherein the feeding section is optionally thermallycontrolled; a mixing section configured to receive the material from thefeeding section and mix, melt, and/or blend the material, wherein themixing section comprises a die; a pelletizing section configured toreceive the material from the mixing section and pelletize the material,wherein the pelletizing section comprises: a cutter hub comprising ablade angle of less than about 90 degrees; and a transport fluid boxcomprising an inlet and an outlet to reduce a velocity of transportfluid into and through the transport fluid box, wherein the outletreduces any obstruction of pellets leaving the transport fluid box byproviding an open area; a system of non-linear transport pipingdownstream of the transport fluid box; an agglomerate catcher downstreamof the pelletizing section, wherein the agglomerate catcher comprises anangled agglomerate removal grid, and wherein the non-linear transportpiping is configured to allow transport of the material from thepelletizing section to the agglomerate catcher; a defluidizing sectiondownstream of the agglomerate catcher, wherein the defluidizing sectioncomprises a pellet feed chute; a drying section configured to receivethe material from the defluidizing section and dry the pelletizedmaterial, wherein the drying section comprises a dryer having at leastone circumferential screen about a rotor; a pellet diverter valvedownstream of the drying section, wherein the pellet diverter valvecomprises: an inlet configured to receive an incoming flow of pelletsfrom the drying section; and at least a first and second outlet, eachconfigured to dispense an outgoing flow of pellets; at least a first andsecond bagging assembly in communication with at least the first andsecond outlets of the pellet diverter valve, respectively, wherein theat least the first and second bagging assemblies are configured toalternatingly receive a specific quantity of pellets from the pelletdiverter valve to allow continuous bagging of the pellets; and a surfacetreatment applied to at least a portion of a surface of a component ofthe feeding section, mixing section, pelletizing section, transportpiping, agglomerate catcher, defluidizing section, drying section,pellet diverter valve, and/or bagging assemblies to reduce abrasion,erosion, corrosion, wear, and undesirable adhesion and stricture,wherein the surface treatment comprises at least two layers such thatthe surface formed following treatment is three-dimensionally textured,wherein the at least two layers comprise at least one layer of awear-resistant material that is uniformly overcoated with a non-stickpolymer that only partially fills the three-dimensional surface textureof the at least one layer of wear-resistant material.
 2. The system forcontinuously bagging tacky materials of claim 1, the mixing sectioncomprising a die comprising a removable insert.
 3. The system forcontinuously bagging tacky materials of claim 2, wherein the removableinsert has a taper angle that is less than or equal to about 25 degrees.4. The system for continuously bagging tacky materials of claim 2,wherein a gap between the removable insert and a body of the die is lessthan or equal to about 0.010 inches.
 5. The system for continuouslybagging tacky materials of claim 2, wherein a face of the removableinsert extends beyond a surface edge of a body of the die less than orequal to about 0.080 inches.
 6. The system for continuously baggingtacky materials of claim 1, wherein the mixing section comprises a diecomprising a removable insert with a taper angle that is less than orequal to about 10 degrees, wherein a gap between the removable insertand a body of the die is less than or equal to about 0.005 inches, andwherein a face of the removable insert extends beyond a surface edge ofthe die body between about 0.060 inches and about 0.080 inches.
 7. Thesystem for continuously bagging tacky materials of claim 1, wherein thecutter hub is streamlined to have an extended hexagonal cross-section.8. The system for continuously bagging tacky materials of claim 1,wherein the blade angle of the cutter hub is between about 20 degreesand about 60 degrees.
 9. The system for continuously bagging tackymaterials of claim 1, the cutter hub further comprising a blade cuttingangle that is less than or equal to about 15% less than the blade angle.10. The system for continuously bagging tacky materials of claim 1, thecutter hub further comprising a blade traverse angle that is betweenabout 20 degrees and about 55 degrees.
 11. The system for continuouslybagging tacky materials of claim 1, wherein the cutter hub comprises ablade angle of about 30 degrees to about 50 degrees, a blade cuttingangle less than or equal to about 15% less than the blade angle, and ablade traverse angle of between about 20 degrees and about 55 degrees.12. The system for continuously bagging tacky materials of claim 1,wherein the die of the mixing section comprises a die hole having a landthat is continuous.
 13. The system for continuously bagging tackymaterials of claim 1, wherein an angle of inclination of the angledagglomerate removal grid is at least about 20 degrees.
 14. The systemfor continuously bagging tacky materials of claim 1, wherein an angle ofinclination of the angled agglomerate removal grid is at least about 50degrees.
 15. The system for continuously bagging tacky materials inclaim 1, wherein the at least one layer of wear-resistant material ofthe surface treatment is a ceramic.
 16. The system for continuouslybagging tacky materials of claim 1, wherein the non-stick polymer of thesurface treatment is a silicone, fluoropolymer, or a combinationthereof.
 17. The system for continuously bagging tacky materials ofclaim 1, the drying section further comprising rotor blades in an upperportion of the rotor that are at least about 20% narrower than rotorblades of a lower portion of the rotor.
 18. A method for continuouslybagging tacky materials, the method comprising: feeding material into afeeding section, wherein the feeding section is optionally thermallycontrolled; mixing, melting, and/or blending the material at a mixingsection, the mixing section also extruding the material through a die;receiving, at a pelletizing section, the material from the die of themixing section, the pelletizing section pelletizing the material, thepelletizing comprising: cutting the material by a cutter hub to formpelletized material; and receiving, by a transport fluid box withtransport fluid therein, the pelletized material; transporting, througha system of non-linear transport piping, the pelletized material;removing, by an agglomerate catcher, agglomerate in the transport fluid,wherein the agglomerate catcher comprises an angled agglomerate removalgrid, and wherein the non-linear transport piping transports thepelletized material from the pelletizing section to the agglomeratecatcher; defluidizing, by a defluidizing section, the pelletizedmaterial; drying, by a drying section, the pelletized material;diverting, by a pellet diverter valve, the pelletized material into afirst bagging assembly or a second bagging assembly; and bagging, at thefirst and second bagging assembly, the pelletized material in a mannerthat enables continuous bagging of the pellets.
 19. The method forcontinuously bagging tacky materials of claim 18, wherein the pelletdiverter valve diverts the pelletized material into the first and secondbagging assemblies in an alternating manner.
 20. A pellet bagged by themethod of claim 18.